1. Field of the Invention
The present invention relates to a secondary battery and capacitor, and more particularly to a secondary battery and capacitor in which an indole polymeric compound is used as an electrode active material and a proton is employed as a charge carrier thereof.
2. Description of the Related Art
As an invention that employs indole, JP 5-148320A discloses a method of chemical-oxidative polymerization of indole monomers to obtain polyindole, and a conductive device that contains polymers polymerized through the method. The indole is limited only to the polyindole and the use of the conductive device is only for conductive films and electrochromic devices.
A paper on “Electrochemical synthesis of polyindole and its evaluation for rechargeable battery applications” describes a battery composed of Zn/ZnSO4/Polyindole. This battery employs a neutral electrolytic solution. The reaction of the battery in the neutral electrolytic solution is accompanied with doping and de-doping of dopant anions. These dopant anions are large in size and low in mobility. Accordingly, this battery is disadvantageous to performances of fast charging and discharging.